Fenics 2019.1.0 and dolfinx v0.6.0

[dokken]

Why would you do that? It is less accurate.

If you really want to decrease the accuracy, you could interpolate the ufl expression into a dolfinx function, as mentioned in

Using ufl for manifactured solutions

The interface to interpolate ufl-expressions is not quite as you tried to use it. You need to use dolfinx.fem.Expression as a wrapper around the ufl-expression. This is shown of in various places: https://jsdokken.com/dolfinx-tutorial/chapter1/membrane_code.html?highlight=fem+expression#interpolation-of-a-ufl-expression https://jsdokken.com/dolfinx-tutorial/chapter4/convergence.html?highlight=fem+expression#reliable-error-norm-computation https://jsdokken.com/fenics22-tutorial/heat_eq.html#…